García-Herruzo, F.

García-Rubio, A.

Gómez-Lahoz, C.

Merchán, M.C. Rey

Paz-Garcia, Juan Manuel

Rodríguez-Maroto, J.M.

Vereda-Alonso, C.

Online Research Database In Technology

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Downloaded from orbit.dtu.dk on: Dec 19, 2017A Procedure for the Selection of the Optimal Extractant Agent for the ElectrokineticRemediation Treatment of Heavy Metals Contaminated SoilsAbstract of poster presentationMerchán, M.C. Rey; García-Rubio, A.; Vereda-Alonso, C.; Gómez-Lahoz, C.; García-Herruzo, F.; PazGarcia, Juan Manuel; Rodríguez-Maroto, J.M.Published in:2011 EREM : Developments in Electrokinetic Remediation of Soils, Sediments and Construction MaterialsPublication date:2011Document VersionEarly version, also known as pre-printLink back to DTU OrbitCitation (APA):Merchán, M. C. R., García-Rubio, A., Vereda-Alonso, C., Gómez-Lahoz, C., García-Herruzo, F., Paz-Garcia, J.M., & Rodríguez-Maroto, J. M. (2011). A Procedure for the Selection of the Optimal Extractant Agent for theElectrokinetic Remediation Treatment of Heavy Metals Contaminated Soils: Abstract of poster presentation. In2011 EREM : Developments in Electrokinetic Remediation of Soils, Sediments and Construction Materials (pp.171-172)A Procedure for the Selection of the Optimal Extractant Agent for the Electrokinetic Remediation Treatment of Heavy Metals Contaminated Soils   M.C. Rey MerchánA, A. García-RubioA, C. Vereda-AlonsoA, C. Gómez-LahozA, F. García-HerruzoA, J.M. Paz-García*B and J. M. Rodríguez-MarotoA   A Department of Chemical Engineering, University of Málaga, Campus de Teatinos, 29071 Málaga, Spain B Department of Civil Engineering, Technical University of Denmark, 2800-Kgs. Lyngby, Denmark * Corresponding author at: jugra@byg.dtu.dk, Tel: +45 4525 5029, Fax: +45 4588 3282   Introduction  The efficiency of the electrokinetic remediation treatments on heavy metals contaminated soils is strongly limited by the chemical species of the different metals in the soil [1-2]. Thus, different results are obtained from electrokinetic treatments of soils applied to an actual contaminated site and a similar clean soil spiked in the laboratory. The changes of the metallic species during the electroremediation are also important. If the basic front generated by the electrode reactions at the cathode is not controlled, heavy metals may precipitate in the form of insoluble hydroxides, making the treatment inefficient. Therefore, in order to characterize all these processes, procedures of sequential extraction, such as BCR (Communitie Bureau of Reference), are used to split the total metal content in fractions with different mobility [3].  On the other hand, acid enhanced electrokinetic treatments have been one of the most accepted techniques for heavy metal electrokinetic remediation. Low pH is assured in the soil during the process, by the use of selective membranes or acidic substances, increasing the mobilization of the metals. Although the technique has shown high effectiveness, in the cases of soils with high buffer capacity the acid enhanced technique can be inefficient, since an enormous amount of electrical energy is necessary to obtain the aimed acid environment. Furthermore, the process can modify in a significant manner the physiology of the soil, and reduce or eliminate permanently the buffer capacity of the treated soil.  The use of specific extractant agents seems to be an interesting alternative to improve the mobilization of the contaminants. The main idea is to obtain a soluble compound, normally a complex ion, by means of a chemical reaction between the target heavy metal and the extractant agent. Thus, this technique not only improves the general efficiency of the removal, avoiding the side effects of the use of acids, but also allows a selective mobilization of the contaminants which can be of interest for different purposes, such as the economical exploitation of the collected heavy metals. In addition to this, the use of extractant agents can be combined, in a sequential or in a simultaneous treatment, such as, for instance, the aforementioned acid enhanced technique.  In the present study, a procedure for the selection of the optimal extractant agent for a contaminated soil is described. In a first step, multi-species chemical equilibrium software is used for the identification of the best candidates to be useful extractant agents for a specific system. Subsequently, leaching experiments in a well stirred tank are performed, to verify the results of the theoretical equilibrium analysis, as well as to determine the feasibility of the process from the kinetic point of view.   The effectiveness of the selected extractant agents are verified in both flushing and/or electrokinetic treatment depending on the soil permeability.  Acknowledgements The authors thank Prof. Carmen Hidalgo Estevez from the Department of Geology/EUP Linares, University of Jaen for the localization of soils and acknowledge the financial support of the Ministerio de Ciencia e Innovación of the Spanish Government through the project ERHMES, CTM2010-16824.  References 1.- A.V. Filgueiras, I. Lavilla, C. Bendicho, Chemical sequential extraction for metal partitioning in environmental solid samples, J. Environ. Monit. 4 (2002) 823-857.  2.- A.M. Ure, C.M. Davidson, R.P. Thomas, Single and sequential extraction schemes for trace metal speciation in soil and sediment. in: Ph Quevauviller, E.A. Maier, B. Griepin (Eds.), Quality Assurance for Environmental Analysis, Elsevier Science B.V., Amsterdam, 1995, pp. 505-523.  3.- A.M. Ure, P. Quevauviller, H. Muntau, B. Griepink, Speciation of heavy metals in soils and sediments. An account of the improvement and harmonization of extraction techniques undertaken under the auspices of the BCR of the commission of the European Communities, Int. J. Environ. Anal. Chem. 5:1-4 (1993) 135-151. 

A Procedure for the Selection of the Optimal Extractant Agent for the Electrokinetic Remediation Treatment of Heavy Metals Contaminated Soils:Abstract of poster presentation

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A Procedure for the Selection of the Optimal Extractant Agent for the Electrokinetic Remediation Treatment of Heavy Metals Contaminated Soils:Abstract of poster presentation

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